For example, in a related art hinge mechanism, the separation of a shaft from a shaft receiving unit can be prevented by screwing a C-shaped ring to a supporting unit.
However, according to the related art hinge mechanism, as a screw process is required, it is difficult to reduce the number of the assembly processes. In view of the above, the object of the invention is to provide such a hinge mechanism that assembly work using working tools such as the screw process can be eliminated, and the object of the invention is to reduce the manufacturing costs of the image forming apparatus by using the hinge mechanism.